Supporters of the “Bristol Bay Forever” proposal will have up to a year to gather the at least 30,169 signatures required to get the measure on the ballot in 2014.

Treadwell certified the proposal on the recommendation of Attorney General Michael Geraghty, whose office said some provisions might give rise to constitutional concerns but were insufficient to bar certification.

“Our role is not to identify every conceivable constitutional vulnerability in an initiative bill and invoke those vulnerabilities to recommend denial of certification,” the review states, adding later: “You have the authority to deny certification only if you determine that the measure violates any of the liberally construed constitutional and statutory provisions regulating initiatives. As discussed above, we do not believe such violations exist.”

The proposal would require legislative approval for a “large-scale metallic sulfide mining operation,” which is defined as a mining proposal to extract metals including gold and copper from sulfide-bearing rock and directly disturb 640 acres of land or more. The proposal does not specifically name the Pebble Mine project but would almost certainly affect it.

Mike Heatwole, a spokesman for the Pebble Limited Partnership, the group behind the proposed mine, expressed regret “that this unconstitutional and ill-conceived proposal will move forward.”

“Pebble is committed to complying with all applicable laws and believes that the proposal would introduce new, clearly unconstitutional measures,” Heatwole said. “We are hopeful that Alaskans will reject this attempt to inappropriately politicize the already rigorous permitting process.”

For years, an intense public relations war has been waged around the mine project, a large copper and gold prospect near the headwaters of the largest sockeye salmon fishery in the world. Pebble Limited Partnership has called the deposit one of the largest of its kind in the world, with the potential of producing 80.6 billion pounds of copper, 107.4 million ounces of gold and 5.6 billion pounds of molybdenum.

In the initiative application packet, attorney Tim McKeever said the Legislature in 1972 acknowledged the cultural and economic importance of the Bristol Bay region by establishing the Bristol Bay Fisheries Reserve to protect salmon from the impact of oil and gas development.

That measure says the Legislature can only approve any oil and gas development proposed within the reserve if it doesn’t endanger the fishery. Supporters of the proposed initiative say their plan would simply apply these provisions to any large-scale mining activity.

A bill similar to the proposed initiative was introduced during the last legislative session but died.